Lesnar and Carwin first fought at UFC 116 in July 2010. In the title-unification bout, Carwin nearly forced a first-round TKO stoppage, but Lesnar survived the ground-and-pound attack and secured a fight-ending arm-triangle choke in the following round. Neither fighter won another MMA bout.

Lesnar (5-3 MMA, 4-3 UFC) lost the title to now-reigning champ Cain Velasquez in his next fight and then announced his UFC retirement after a subsequent TKO loss to Alistair Overeem in late 2011. He later rejoined the WWE, where he’s again emerged as one of the pro wrestling organization’s bigger draws.

Carwin (12-2 MMA, 4-2 UFC), meanwhile, subsequently suffered a decision loss to Junior dos Santos, and after a lengthy injury hiatus, ultimately announced his official MMA retirement earlier this year.

And adding further fuel to the fire, the UFC is making a special announcement at 6 p.m. ET tonight prior to UFC 168. While the announcement could be related to the UFC’s new digital network, a recent Carwin tweet suggests perhaps it’s something else.